We request a Zeiss LSM 510MP microscope for the multiphoton-excited fluorescence imaging of a variety of cells, tissues and organisms. The Zeiss 510MP is a dedicated multiphoton-excitation system, thus complementing four confocal microscopes, including two Zeiss 510-Meta confocals, already in the School of Medicine Microscope Facility. As the largest core microscope facility on campus, our well-trained staff and established resources already serves over 250 users annually. However, there is no multiphoton microscope available for regular, general use by NIH-funded investigators. Existing instruments are inaccessible for a number of reasons. Furthermore, recent advances in laser technologies (Spectra-Physics MaiTai DeepSee) greatly facilitate state-of-the-art multiphoton fluorescence microscopy in a multi-user core facility. Initially, the system will serve 5 major users and potentially 60 minor users from multiple departments throughout Johns Hopkins. Because multiphoton fluorescent imaging provides unprecedented depth and sensitivity of imaging in living samples, we expect that minor users will slowly become major users. Supported by a broad base of interest, need, and financial support by the University, and will serve a large NIH-funded scientific community. [unreadable] [unreadable] [unreadable]